Robert Verkaik: The wall of silence erected by those in the know

Analysis

The Crown Prosecution Service's decision not to bring phone-hacking charges against Andy Coulson may amount to no more than a brief respite for the former editor of the News of the World.

The Prime Minister's spin doctor has become so closely associated with the politically charged allegations that yesterday's legal developments in Scotland are unlikely to put an end to the scandal.

There is a stench of disbelief over what Mr Coulson says he knew about the illegal actions of at least one of his reporters who intercepted the personal mobile phones of public figures.

Yesterday Mr Coulson's evidence as a witness in the perjury trial of former MSP Tommy Sheridan and his wife Gail added more smoke to the fire.

He confirmed to the court that he had enjoyed a limited social relationship with Andy Hayman, the assistant commissioner at Scotland Yard who headed the inquiry into the phone-hacking scandal at the paper.

And under cross examination Mr Coulson further told the court that his own private office wasn't searched by Mr Hayman's officers.

Such admissions will raise further questions about the cosy relationship between the Metropolitan Police force and Rupert Murdoch's media empire. When Mr Hayman left the Met in 2007 he was employed by News International as a columnist.

MPs have already criticised the Met for what they saw as a hasty decision to end their original investigation after Goodman and private investigator Glenn Mulcaire were convicted in 2006.

Yesterday the CPS's decision not to bring further charges confirmed what many people already suspected, that the investigation had been met with a wall of silence. Had former News of the World reporter Sean Hoare not declined to repeat to officers what he had told the New York Times about questionable news-gathering practices at the paper, yesterday's news may have been much more gloomy for Mr Coulson.

But Mr Coulson and his new employer must be aware that it only takes one insider to break ranks for the police investigation to be reignited.